[email protected] Google Data APIs - 2009 Google Data APIs : Integrando suas aplicações Java com os serviços Google.

[email protected] Google Data APIs - 2009 http://pcmnac.com

Google Data APIs :Integrando suas aplicações Java com os

serviços Google


Available APIs

source: http://code.google.com/apis/gdata


Practical Usage

• Google data APIs are not read-only!


Practical Usage

• Manage user’s Gmail contacts programmatically• Synchronize user’s Gmail contacts on a mobile

device• Import user’s Gmail contacts to a social application• Manage user’s Google Calendar events• Backup and share and convert user’s documents• Create and publish Posts• Publish user’s photos and videos• Integrate Google services• Remote repository (Contacts, Events, Documents,

Images, Videos, etc)


Application Requirements

• Make HTTP requests – At least GET and POST

• Handle XML messages– JSON can be used


How it works?

• APIs are available in form of RESTful web services

• There is a well-defined protocol used– Atom based


GData Protocol


Background

• REST Web Services

• Web Feeds


REST Web Services

• Based on HTTP methods:– POST (Create)– GET (Retrieve)– PUT (Update)– DELETE (Delete)

• Basic request members:– HTTP Method – Resource URI– Request Body (Optional)


REST Web Services

• Request examples:

HTTP Method Resource URI

GET http://myservice.com/users

GET http://myservice.com/users/5

DELETE http://myservice.com/users/5

POST http://myservice.com/users

PUT http://myservice.com/users/6


Web Feeds

• Frequently updated content (Wikipedia)• Common Formats

– RSS– Atom (GData default format)

• Feed• Entry


Atom Feed Example<feed xmlns="http://www.w3.org/2005/Atom"> <title>My Feed</title> <updated>2008-09-23T08:30:00-03:00</updated> <id>http://www.example.com/myFeed</id> <author> <name>pcmnac</name> </author> <link href="/myFeed" rel="self"/> <entry> <id>http://www.example.com/id/1</id> <link rel="edit" href="http://www.example.com/myFeed/1/1/"/> <updated>2008-09-24T08:30:00-03:00</updated> <author> <name>John</name> <email>[email protected]</email> </author> <title type="text">My Entry</title> <content type="text">My content</content> </entry> <entry> ... </entry></feed>


GData Protocol

• Based on HTTP methods:– POST (Create)– GET (Retrieve)– PUT (Update)– DELETE (Delete)


GData – Retrieving DataGET http://www.myservice.com/myfeed

200 OK

<feed xmlns="http://www.w3.org/2005/Atom">

<title>My Feed</title>

<updated>2008-09-23T08:30:00-03:00</updated>

<id>http://www.myservice.com/myfeed</id>

<author>

<name>pcmnac</name>

</author>

<link href="/myfeed" rel="self"/>

<entry>

...

</entry>

</feed>

Request:

Response:


GData – Creating Data

POST http://www.myservice.com/myfeed

<entry> <author> <name>John</name> <email>[email protected]</email> </author> <title type="text">My Entry</title> <content type="text">My content</content></entry>

Request:


GData – Creating Data

201 CREATED

<entry>

<id>http://www.myservice.com/myfeed/1</id>

<link rel="edit" href="http://www.myservice.com/myfeed/5/1/"/>


<author>

<name>John</name>

<email>[email protected]</email>

</author>

<title type="text">My Entry</title>

<content type="text">My content</content>

</entry>

Response:


GData – Updating Data

PUT http://www.myservice.com/myfeed/5/1

<entry xmlns='http://www.w3.org/2005/Atom' xmlns:gd='http://schemas.google.com/g/2005' gd:etag='"CUUEQX47eCp7ImA9WxRVEkQ."'> <id>http://www.myservice.com/myfeed/5</id> <link rel='edit' href='http://www.myservice.com/myfeed/5/1/'/> <updated>2008-09-24T08:30:00-03:00</updated> <author> <name>John</name> <email>[email protected]</email> </author> <title type="text">My Entry</title> <content type="text">My content</content></entry>

Request:


GData – Updating Data

200 OK

<entry xmlns='http://www.w3.org/2005/Atom'

xmlns:gd='http://schemas.google.com/g/2005'

gd:etag='"FkkOQgZGeip7ImA6WhVR"'>

<id>http://www.myservice.com/myfeed/5</id>

<link rel='edit' href='http://www.myservice.com/myfeed/5/2/'/>


<author>

<name>John</name>

<email>[email protected]</email>

</author>

<title type="text">My Entry</title>

<content type="text">My content</content>

</entry>

Response:


GData – Deleting Data

DELETE http://myservice.com/myfeed/5/1

Request:

200 OK

Response:


Project 1

Google Contacts Manager


Project 2

Google PDF Converter